1. Field of the Invention
The present invention relates to a vehicle-use electricity management system for managing electricity used to drive an electrical load mounted on a vehicle, a vehicle-use electricity information management apparatus for use in the vehicle-use electricity management system, and a vehicle-use electrical load.
2. Description of Related Art
Types and electricity consumption of electrical loads mounted on a vehicle (may be referred to simply as load(s) hereinafter) are steadily increasing. Accordingly, it is required to reduce overall electricity consumption and to increase energy usage efficiency of a vehicle (reduction of CO2 discharge, for example). To this end, various techniques to properly manage supply-demand relationship of electricity for a vehicle are proposed.
Such techniques includes one which optimally distributes electricity generated by an alternator among a plurality of electrical loads, as described in Japanese Patent Application Laid-open No. 2004-194495, for example. The technique described in this patent document operates such that an electricity supply control means sets (changes) priorities and electricity demand of electrical loads mounted on a vehicle depending on temporal changes of a vehicle state and states of the electrical loads, and a load control means controls distribution of electricity among the electrical loads, and electricity consumptions of the electrical loads in accordance with the settings made by the electricity supply control means.
However, to implement the technique described in the above patent document, a large space to accommodate various components has to be provided and a high cost to provide the various components has to be accepted, because the technique needs a structure to selectively make or break electricity supply paths or electricity distribution paths leading to the electrical loads.
Further, distribution of electricity and making or breaking of electricity supply paths are controlled mostly by the electricity supply control means. That is, electricity supply to the respective electrical loads are put under centralized control of the electricity supply control means.
Accordingly, to mount the electricity supply control means implemented as a product on a vehicle, it is necessary to build or design an electricity management system including the electricity supply control means taking into account usage conditions (important particulars and design philosophy, for example) and behaviors (operating specifications and design specifications, for example) of the electrical loads, and also reactions occurring when electricity supply to the electrical loads is interrupted.
That is, to implement the electricity supply control means as a product, extensive technological knowledge and enormous man-hours regarding the whole system including both the electricity supplying side and the electricity consuming side are needed. Hence, it is difficult to implement such an electricity supply control means as a product because of burden of ensuring a necessary quality and reducing a developing cost. Particularly, for recent vehicles highly systemized such that a plurality of electrical loads operate in cooperation with one another to carry out one function, it is very difficult to implement an electricity management system capable of performing electricity management appropriately taking into account of such conditions and reactions of all the electrical loads.
Further, in each of the electrical loads, permission of receiving electricity to itself, and accordingly permission of starting operation of itself follows instructions received from outside (for example, instructions received from the electricity supply control means). Accordingly, each electrical load has to be designed to accept unexpected interruption of supply of electricity.
That is, persons in charge of designing or developing electrical loads have a burden to provide the electrical loads with capability of following instructions received from outside while ensuring the same safety level and function level as those of conventional electrical loads. By the reasons described above, the persons in charge of designing or developing electrical loads are reluctant to adopt the technique as described in the foregoing patent document.